1. Technical Field
The present invention relates generally to high-performance, fault-tolerant web content delivery.
2. Description of the Related Art
It is known in the prior art to distribute media-rich web objects away from busy home sites to a network of content servers located across multiple major Internet backbone networks. One such service (CDS) is known as FreeFlowSM content delivery, which is available from Akamai Technologies, Inc. of Cambridge, Mass. Akamai operates a global content delivery network (CDN) comprising a large number of distributed content servers, network mapping servers, and associated mechanisms to track reporting and administration of its content delivery service. The Akamai content servers are typically located at edge-of-network access points such as Internet Points-of-Presence (POPs).
In operation of the FreeFlow content delivery service, a software tool is used to tag embedded web page objects, such as graphics and images, for delivery via the CDN. Typically, the objects are tagged by transforming web page Uniform Resource Locators (URLs) that identify those objects. The objects identified by the modified URLs are then hosted on the CDN content servers. In one typical user interaction with a web site enabled by FreeFlow, the user's browser sends a request for a web page to the site. In response, the web site returns the page markup language (e.g., HTML) code as usual, except that the embedded object URLs have been modified to point to the content delivery network. As a result, the browser next requests and tries to obtain the media-rich embedded objects from an optimally-located CDN server, instead of from the content provider's site. The above-described web content delivery service provides significant advantages, namely, faster downloads for end-users, reduced load on the home site, flash crowd protection, easier web site management and infrastructure scaling, and the ability to distribute media-rich objects effectively. Further details of the Akamai CDN and service are described in U.S. Pat. No. 6,108,703, which is incorporated herein by reference.
CDN customers (namely, content providers) may want to purge objects from the CDN from time-to-time. This need may arise, for example, because the customer has published the wrong object and needs to remove it before the object's normal time-to-live (TTL) expires. Another reason a customer may desire to purge an object is because an error occurred during the tagging of the object, e.g., an object is given a 1-day TTL instead of a 30 minute TTL. Other reasons purging may be required are unauthorized publishing of an object, publishing an object with the wrong object name, or the like. CDN system administrators may also have a need to purge given content. In addition, where CDN servers are used to provide dynamic content assembly on behalf of the content provider, it is desired to maintain the content provider's publishing and content management environment, and such environment may include the ability to remove particular content.
To this end, it would be desirable to provide a mechanism to enable the CDN content provider customer and/or the CDN administrator the ability to selectively remove content from the CDN. The present invention addresses this need.